<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>css 转圈</title>
  <style>
    .turn{
      width:100px;
      height: 100px;
      background: aqua;
      animation:turn 1s linear infinite;      
      margin: 100px auto;
    }
    /* 
      turn : 定义的动画名称
      1s : 动画时间
      linear : 动画以何种运行轨迹完成一个周期
      infinite :规定动画应该无限次播放
     */
    @keyframes turn{
      0%{-webkit-transform:rotate(0deg);}
      25%{-webkit-transform:rotate(90deg);}
      50%{-webkit-transform:rotate(180deg);}
      75%{-webkit-transform:rotate(270deg);}
      100%{-webkit-transform:rotate(360deg);}
    }
  </style>
</head>
<body>
  <div class="turn"></div>
</body>
</html>